Wellcome Trust Center for Neuroimaging, University College London, London WC1N 3AR, United Kingdom.
Proc Natl Acad Sci U S A. 2010 Aug 24;107(34):15005-10. doi: 10.1073/pnas.1002258107. Epub 2010 Aug 9.
Decision-making often involves choices between different stimuli, each of which is associated with a different physical action. A growing consensus suggests that the brain makes such decisions by assigning a value to each available option and then comparing them to make a choice. An open question in decision neuroscience is whether the brain computes these choices by comparing the values of stimuli directly in goods space or instead by first assigning values to the associated actions and then making a choice over actions. We used a functional MRI paradigm in which human subjects made choices between different stimuli with and without knowledge of the actions required to obtain the different stimuli. We found neural correlates of the value of the chosen stimulus (a postdecision signal) in ventromedial prefrontal cortex before the actual stimulus-action pairing was revealed. These findings provide support for the hypothesis that the brain is capable of making choices in the space of goods without first transferring values into action space.
决策通常涉及在不同的刺激物之间进行选择，每个刺激物都与不同的物理动作相关联。越来越多的共识表明，大脑通过为每个可用选项分配一个值，然后对它们进行比较来做出选择。决策神经科学中的一个悬而未决的问题是，大脑是通过在商品空间中直接比较刺激物的价值来计算这些选择，还是首先为相关动作分配值，然后再在动作之间做出选择。我们使用了一种功能磁共振成像范式，在该范式中，人类受试者在知道获得不同刺激所需的动作的情况下和不知道的情况下，在不同的刺激物之间做出选择。我们发现，在实际的刺激-动作配对被揭示之前，腹内侧前额叶皮层中就存在所选刺激的价值的神经相关性（决策后信号）。这些发现为假设提供了支持，即大脑能够在不先将值转换为动作空间的情况下，在商品空间中做出选择。
